This invention relates to sealing of cables. More particularly, this invention relates to wrap-around cable sleeves.
In the electrical utilities industry, maintaining cable integrity may be critical. A loss of cable integrity, for example, a short circuit in a high voltage cable, may result in a crippling power outage, or, even worse, a loss of life. One everyday task that may pose a great threat to cable integrity is the formation of electrical connections.
When electrical connections are formed, a bare metal surface may be exposed such as a splice connector. These bare metal surfaces may be particularly hazardous when formed in the field where they are exposed to the environment. This environment may include rocks and other sharp objects as well as moisture when the connection is to be buried under ground and rainfall when the connection is to be suspended in the air. Thus, there is a need to protect such electrical connections from the environment.
U.S. Pat. No. 5,828,005 to Huynh-Ba et al. proposes the use of a gel-filled closure for environmentally protecting a connector forming a connection between a cable and at least one electrical component. The closure may include first and second cavitied bodies, each having two lateral sides and two end sides. The closure may have a hinge joining the first and second bodies along a lateral edge. The closure may be integrally made of a thermoplastic material by injection molding. The thermoplastic material may have a tensile yield strength of at least 3,500 psi. The closure may include reinforcing ribs which decrease the deflection in the closure near fingers as the enclosed gel expands during service at elevated temperatures.
While the gel may protect the connection from moisture and the closure may provide protection from rocks and other buried sharp objects, such a solution may ultimately be less than optimal. The reinforcing ribs may need to be designed to withstand a given internal pressure. As a result, valuable engineering resources may need to be expended to create a satisfactory closure. Moreover, standard electrical connectors are typically not used by electrical utilities across the country. Instead, connectors may assume a variety of shapes and sizes. As the above closure may be formed in molds by injection molding, large capital investments may be required to manufacture them. Oftentimes, the ultimate market for these specialty closures may not be large enough to warrant such an investment. Furthermore, the gel may have to be placed in the closures in a discrete step, either in the manufacturing process or in the field, which may be inefficient.
U.S. Pat. No. 4,888,070 to Clark et al. proposes a flexible envelope having therein a scaling material. As noted above, gels may expand when heated causing internal stresses on the flexible envelope. If the flexible envelope is made of an elastomer having sufficient elasticity to absorb the expansion of the gel, the closure may become susceptible to splitting if placed in contact with a sharp object such as a rock. If the flexible envelope is made of a rigid material capable of withstanding such contact, the closure may become susceptible to stresses similar to those encountered by the closure, as noted above. Furthermore, the gel may typically be positioned within the flexible envelope in the field. Providing the gel in a discrete step may be inefficient.
According to the present invention, wrap-around cable sleeves for environmentally sealing a cable section are provided. The wrap-around cable sleeve may include a longitudinally extending body made from an electrically insulating material and having a longitudinally extending portion that has a corrugated lateral cross-section. The longitudinally extending portion may have a flexural modulus of between about 4,000 and 100,000 psi. The longitudinally extending portion in various embodiments defines a portion of a cable chamber. The cable chamber may extend at least substantially around the cable section when the body is wrapped around the cable section. The cable chamber may have a range taking in a radial direction of at least about 15 percent.
In embodiments of the present invention, the longitudinally extending portion may include a first longitudinal edge and a second longitudinal edge laterally spaced from the first longitudinal edge. The wrap-around cable sleeve may further include a connector having a first connecting portion adjacent the first longitudinal edge and a second connecting portion adjacent the second longitudinal edge. The first connecting portion may be positioned adjacent the second connecting portion when the body is wrapped around the cable portion.
In other embodiments of the present invention, the connector may include a connecting member that connects the first connecting portion to the second connecting portion. The connecting member may include longitudinally extending sleeves, spring clamps, and latch members, for example.
In other embodiments of the present invention, the wrap-around cable sleeve may further include a sealant material positioned within the cable chamber. The sealant material may include a silicone gel. The body may further include a first collar portion adjacent a first end of the cable chamber and a second collar portion adjacent a second end of the cable chamber. The first and second collar portions may have a range taking in a radial direction of less than about 10 percent. The cable chamber may have a range taking in the longitudinal direction of less than about 10 percent.
In further embodiments of the present invention, the wrap-around cable sleeve may include a first restraint member positioned over a first end portion of the cable chamber and a second restraint member positioned over a second end portion of the cable chamber. The second end portion may be longitudinally spaced from the first end portion. The first end portion may have a first slot with the first restraint member positioned therein. The second end portion may have a second slot with the second restraint member positioned therein. The first and second restraint members may limit a range taking in a radial direction of the first and tie second cable chamber end portions to less than about 10 percent.
In yet other embodiments of the present invention, the electrically insulating material may include a thermoplastic elastomer. The thermoplastic elastomer may be selected from the group consisting of polypropylene/rubber blends and polyurethanes. The longitudinally extending portion may have a 100% tensile modulus of between about 250 psi and 3000 psi and may have a tension set of less than about 60 percent.
In other embodiments of the present invention, a wrap-around cable sleeve for environmentally sealing a cable section is provided which includes a longitudinally extending body comprising an electrically insulating material and having a longitudinally extending portion. The longitudinally extending portion may have a first longitudinial edge and a second longitudinial edge laterally spaced from the first longitudinal edge. The longitudinally extending portion may define a portion of a cable chamber. The cable chamber may extend at least substantially around the cable section when the body is wrapped around the cable section. The cable chamber may have a range taking in a radial direction of at least about 15 percent and may have a range taking in the longitudinal direction of less than about 10 percent. The wrap-around cable sleeve may include a connector having a first connecting portion adjacent the first longitudinal edge, and a second connecting portion adjacent the second longitudinal edge.
In further embodiments of the present invention, a wrap-around cable sleeve for environmentally sealing a cable section is provided which includes a longitudinally extending body made from an electrically insulating material and having a longitudinally extending portion with a corrugated lateral cross-section. The longitudinally extending portion may have a first longitudinal edge and a second longitudinal edge laterally spaced from the first longitudinal edge. The longitudinally extending portion may have a range taking in a lateral direction of at least about 15 percent and a flexural modulus of between about 4,000 and 100,000 psi. The wrap-around cable sleeve may include a connector having a first connecting portion adjacent the first longitudinal edge and a second connecting portion adjacent the second longitudinal edge. The connector may include a connecting member that connects the first and second connecting portions when the body is wrapped around the cable section. Wrap-around cable closures of the present invention may be present as one or more components in a connection protector kit for environmentally sealing a cable section.
In still other embodiments of the present invention, the body may include an interior surface and an exterior surface when the body is wrapped around the cable section. The wrap-around cable sleeve may include a sealant material on the interior surface of the body to environmentally seal the cable section when the body is wrapped around the cable section.
In other embodiments of the present invention, the body may include a first end portion adjacent a first end of the longitudinally extending portion and extending from the first connecting portion. The first end portion may have a substantially flat lateral cross-section and a range taking in the lateral direction of less than about 10 percent. The body may also include a second end portion adjacent a second end of the longitudinally extending portion and extending from the first longitudinal edge. The second end portion may have a substantially flat lateral cross-section and a range taking in the lateral direction of less than about 10 percent.
In further embodiments of the present invention, a wrap-around cable sleeve for environmentally sealing a cable section is provided including a longitudinally extending body and a connector. The longitudinally extending body may be made from an electrically insulating material and have a longitudinally extending portion with a corrugated lateral cross-section. The longitudinally extending portion may have a first longitudinal edge portion and a second longitudinal edge portion laterally spaced from the first longitudinal edge portion. The connector may include a pin member coupled to and extending from the first longitudinal edge portion and a socket member coupled to and extending from the second longitudinal edge portion. The pin member is preferably configured to connectably engage the socket member. The pin and the socket members are preferably positioned so as to be aligned to connectably engage when the body is wrapped around the cable section.
In other embodiments of the present invention, a lip member may extend from a closure side of the socket member.
In still other embodiments of the present invention, the longitudinally extending portion may have a flexural modulus of between about 4,000 and 100,000 psi, and the pin and socket members each may have a flexural modulus of greater than about 125,000 psi. The connector may include a first connecting portion adjacent the first longitudinal edge portion. The first connecting portion may include a first upright member having an increased lateral cross-section at its distal end. The connector may include a second connecting portion adjacent the second longitudinal edge portion. The second connecting portion may include a second upright member having an increased lateral cross-section at its distal end. The pin member may have a first channel at one end and a pin at an opposite distal end. The first channel may slidably engage the distal end of the first upright member. The socket member may have a second channel at one end and a socket at an opposite distal end. The second channel may slidably engage the distal end of the second upright member.
In further embodiments of the present invention, the pin member may be bonded to the first longitudinal edge portion and the socket member may be bonded to the second longitudinal edge portion. The longitudinally extending portion, the pin member and the socket member may be integrally formed. The pin member and the socket member may include a rigid coating substantially extending over connectably engaging portions thereof to provide the hardness thereof.
In yet other embodiments of the present invention, the pin member may extend substantially entirely along the first longitudinal edge and the socket member may extend substantially entirely along the second longitudinal edge. Alternatively, the pin member may include a plurality of longitudinally spaced pin members, and the socket member may include a plurality of longitudinally spaced socket members. The longitudinally spaced pin members and the longitudinally spaced socket members may be positioned so as to be aligned to connectably engage when the body is wrapped around the cable section.
In still other embodiments of the present invention, the pin member may extend substantially perpendicularly from the body and may have a pin extending from a closure side thereof, and the socket member may extend substantially perpendicularly from the body and may have a socket in the closure side thereof. The closure sides of the pin and socket members may be configured to be adjacent to one another when the body is wrapped around the cable section. An external surface of the pin member and an external surface of the socket member may be configured to provide a grip surface to facilitate wrapping the body around the cable section. An external surface of the pin member and an external surface of the socket member may be configured to receive a locking member. The locking member may be a channel connector that slidably engages the external surfaces of the pin and socket members. Alternatively, the locking member may include a living hinge connected to a first member that is one of the pin member and the socket member and an arm extending from the living hinge and having a hook at an end opposite the living hinge. The arm may extend so as to engage the hook to a second member that is the other of the socket member and the pin member when the arm is rotated to a position adjacent the second member.
Methods of forming a wrap-around cable sleeve are provided by the present invention. The methods of forming a wrap-around cable sleeve may include extruding a web comprising electrically insulating material, applying gel to a surface of the web, and cutting the web having applied gel to form a wrap-around cable sleeve having a first and a second end. The web may include corrugations defining a corrugated lateral cross-section. The web may have a body including a thermoplastic elastomer and may have longitudinal edges including a thermosetting polymer. The applying step may include spraying the gel onto the surface of the web or coextruding the gel onto the surface of the web. The method of forming a wrap-around cable sleeve may include stamping a portion of the web to substantially remove the corrugations therefrom. The stamping operation may be a heat stamping operation. If the cutting operations precede the stamping operations, the first and second ends may be stamped to substantially remove the corrugations therefrom.
In other embodiments of the present invention, methods of forming a wrap-around cable sleeve are provided including extruding a web comprising electrically insulating material to provide a web that includes corrugations defining a corrugated lateral cross section that provides a lateral range taking of at least about 15 percent, cutting the web to form a wrap-around cable sleeve having a first and a second end, and stamping the first and second ends to substantially remove the corrugated cross-sections therefrom. The stamping operation may provide first and second ends, each having a lateral range taking of less than about 10 percent. The stamping operation may be a heat stamping operation. The method may further include applying gel to the web. The applying may precede cutting. Alternatively, the cutting operations may precede applying the gel.
The present invention provides apparatus which may protect an electrical cable section from the environment. More specifically, the present invention provides wrap-around cable sleeves which may protect electrical cable sections of various shapes and sizes from the environment, including moisture as well as sharp objects. The present invention may also provide methods of making such wrap-around cable sleeves.